Archean continental weathering: Revisiting the Sr isotope seawater curve

太古代大陆风化：重温锶同位素海水曲线

• 批准号: 1523697
• 负责人: Clark Johnson
• 金额: $ 21.87万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1523697&HistoricalAwards=false
• 关键词: Archean; continental; weathering; Revisiting; Sr

This award to the University of Wisconsin Madison will help us understand the early Earth and the chemical characteristics of Earth's early oceans. It is interdisciplinary, and could turn over old and ill-constrained paradigms. This proposal will address some very important questions from the Archaean, earlier than 2-1/2 billion years ago: when did plate tectonics begin, how quickly was continental crust built up, did it occur in episodes, how did this affect evolution of life, and how did the emerging continents and their on-board life affect ocean chemistry and the appearance and setting of banded iron formations? Sets of K-12 educational material developed by specialists will be disseminated through the NSF-funded Portal to the Public, and the research results will be used to design and develop illustrations of 'Archean Worlds,' which will be incorporated into tours of the Madison Geology Museum.The work will provide fundamental constraints on the starting date for plate tectonics and the role of lateral tectonic processes. The enhanced understanding of Archean carbonates will bear directly upon the development of banded iron formations, the chief source of iron ore. This work will constrain Archaean topography and hypsometry (the Flat Earth/Water World scenarios). The proponents will refine the existing overly simplistic 87Sr/86Sr Archean seawater curve by looking at seven suites of extremely well characterized marine carbonates. This is a serious attempt at understanding the residence time of Sr in Archaean seawater, and how this may have changed due to changes in the mantle and continental sources. Any new seawater 87Sr/86Sr curve for the Archaean would have a truly transformative effect on our understanding of Archean geochemistry by helping to settle the controversy on whether iron formations and carbonates in the Archean were deposited in restricted basins vs. open ocean, as well as constraining Archaean subareal weathering fluxes of silicic continental material. The project will also use REE+Y systematics to deal with the origin and extent of hydrothermal input vs. continental weathering as well as the oxidation state of Archaean seawater, and perform work on the same samples with C, O, Mg, Fe, and Mo isotopes with funding from NASA.This work is a NSF-NASA inter-agency collaboration on Early Earth.

威斯康星大学麦迪逊分校的奖项将帮助我们了解地球早期的早期和地球早期海洋的化学特征。它是跨学科的，可能会跨越旧的且受到限制的范式。该提案将在2-1亿年前提前解决ARCHAEAN的一些非常重要的问题：板块构造何时开始，大陆壳积累的速度有多快，发生在情节中，这如何影响生命的演变，以及新兴大陆的演变以及板上的生命以及他们的板上生活会影响海洋化学以及带有铁型铁的外观和环境的外观？专家开发的K-12教育材料集将通过NSF资助的门户向公众进行散布，研究结果将用于设计和开发“ Argean Worlds”的插图，该插图将纳入麦迪逊地质博物馆的游览中。这项工作将在板块构造构造的起始日期中提供基本约束，以造成板块构造和侧面的作用。对大帝碳酸盐的增强理解将直接依靠带铁地层的发展，这是铁矿石的主要来源。这项工作将限制天生的地形和催眠（平坦的地球/水世界情景）。支持者将通过查看七个特征良好的海洋碳酸盐套件来完善现有的过于简单的87SR/86SR Archean Seawater曲线。这是一个认真的尝试，以了解SR在古老海水中的停留时间，以及由于地幔和大陆源的变化而导致的情况可能发生了变化。任何新的Seawater 87SR/86SR曲线均用于ARCHAEAN，将通过帮助解决限制性盆地与开阔海洋中是否沉积的铁地层和碳酸盐的争议，对我们对大帝地球化学的理解产生真正的变革性影响，以及限制了Archean sibareal sibareal sibareal sibareal sibareal silentalter材料的硅化物质。 The project will also use REE+Y systematics to deal with the origin and extent of hydrothermal input vs. continental weathering as well as the oxidation state of Archaean seawater, and perform work on the same samples with C, O, Mg, Fe, and Mo isotopes with funding from NASA.This work is a NSF-NASA inter-agency collaboration on Early Earth.